Generally speaking, pigments, when they are dispersed into vehicle for paint or ink, causes agglomeration in the vehicle and such agglomeration causes undesirable phenomena such as aggravation of flow, separation color due to poor compatability with other pigment when the pigment is mixed with other pigment, and lowering of surface gloss.
In order to improve or remove the defects of such pigment, various methods are proposed which include such as (1) surface-treatment of pigment using surface-active agent or metal soap, (2) use of various types of resin and (3) use of various types of derivative of organic pigment. For example, treatment of phthalocyanine blue with calcium salt of rosin is proposed in U.S. Pat. No. 3,296,001, treatment of lithol rubine with metal salt of dialkyl sulfosuccinate is proposed in U.S. Pat. No. 3,582,380 and treatment of phthalocyanine green with aromatic polyester is proposed in U.S. Pat. No. 4,391,648. In U.S. Pat. No. 3,275,637, utilization of derivative of quinacridone pigment and in U.S. Pat. No. 3,532,520, utilization of derivative of disazo yellow are reported, respectively. They are, however, not satisfactory in that those materials do not give non-agglomerating property of pigment to be used, especially, for metallic paint. In fact, metallic paint does not have sufficient clearness nor tinting strength.